The National Organization for Marriage wants Americans to give up their lattes and boycott Starbucks because the coffee chain endorsed marriage equality in Washington state.

The formal boycott announcement coincided with the attendance of NOM representatives at a Starbucks shareholder meeting on March 21 in Seattle, where Starbucks is headquartered.

NOM president Brian Brown stated on March 21, “We respect the important role of businesses in providing goods, services and jobs, and that people of diverse moral views build great companies working together. But Starbucks has corporately, as an organization, endorsed and helped pass gay marriage in the state of Washington. Its executive vice president of partner resources has stated that gay marriage ‘is aligned with Starbucks business practices and upholds our belief in the equal treatment of partners. It is core to who we are and what we value as a company.’ Corporations should not take sides in a culture war that pits a company against half the American people, and nearly all its consumers in some international markets.”

NOM has launched DumpStarbucks.com to promote the boycott.

Joe Solmonese of the Human Rights Campaign, the nation’s largest LGBT civil rights group, said, “NOM is falling back on their typical tactics. Starbucks has been a vocal supporter of marriage equality for loving same-sex couples — views that are in-line with the majority of Americans — and that enrages NOM. As a result, NOM is throwing a temper-tantrum and encouraging its few supporters to intentionally harm the economic well-being of Starbucks employees all over the world.”

Starbucks announced its support of marriage equality early this year, as lawmakers in Washington were preparing to debate legislation.

A law allowing for same-sex couples to marry is set to take effect this summer, but may be delayed because of a ballot campaign to repeal it.